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US3753165A
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Tunable variable bandwidth magneto-elastic filter and method
Assignee: CHU ASS INC US
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Filing: 1971-12-27
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Granted: 1973-08-14
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Expires: 1991-12-27
Abstract
Abstract This disclosure involves one or a plurality of cascaded YIG or similar magneto-elastic media propagating elastic waves transduced from a band of electromagnetic waves and having special magnetic field curved profiles and variable bias magnetic fields applied thereto such as to couple out or absorb the energy of specified variable frequencies to-be-filtered, by effecting conversions of the elastic waves of such specified frequencies only to spin waves. Cascaded units enable a bandpass characteristic to be produced that may be varied in width and center frequency.
Inventors
- 👤 F Morgenthaler
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 16:49
CPC Classifications
H; H03; H03H; H03H9/00; H03H9/30; H03H9/42; H03H9/426; H01; H01P; H01P1/00; H01P1/20; H01P1/215; H01P1/218; H03H9/46
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
149 words
A method of filtering out specified frequencies from a band of electromagnetic wave frequencies, that comprises, transducing the electromagnetic wave frequencies into corresponding elastic waves, propagating the elastic waves through a magneto-elastic medium, re-transducing the propagated elastic waves back into electromagnetic waves after passage through said medium, applying a magnetic field curved profile and bias magnetic field to said medium, the former of such shape and orientation that the bias magnetic field applied to the medium will intersect such profile at points corresponding to predetermined regions of the medium in turn corresponding to the specified frequencies to be filtered out, the field at such regions effeCting conversion of the elastic waves of the specified frequencies only to spin waves with attendant absorption of the energy thereof, and varying the bias magnetic field to vary the position of said regions and thus to vary specified frequencies to be filtered out.
Claim 2
Independent Claim
149 words
A method of filtering out specified frequencies from a band of electromagnetic wave frequencies, that comprises, transducing the electromagnetic wave frequencies into corresponding elastic waves, propagating the elastic waves through a magneto-elastic medium, re-transducing the propagated elastic waves back into electromagnetic waves after passage through said medium, applying a magnetic field curved profile and bias magnetic field to said medium, the former of such shape and orientation that the bias magnetic field applied to the medium will intersect such profile at points corresponding to predetermined regions of the medium in turn corresponding to the specified frequencies to be filtered out, the field at such regions effeCting conversion of the elastic waves of the specified frequencies only to spin waves with attendant absorption of the energy thereof, and varying the bias magnetic field to vary the position of said regions and thus to vary specified frequencies to be filtered out.
Claim 3
Dependent Claim
27 words
A method as claimed in claim 1 and in which said profile and bias field are caused to intersect at a plurality of regions along said medium.
Claim 4
Dependent Claim
20 words
A method as claimed in claim 1 and in which the profile curve rises and then falls along said medium.
Claim 5
Dependent Claim
20 words
A method as claimed in claim 1 and in which the profile curve falls and then rises along said medium.
Claim 6
Dependent Claim
15 words
A method as claimed in claim 1 and in which said medium comprises YIG material.
Claim 7
Dependent Claim
17 words
A method as claimed in claim 1 and in which said elastic waves are longitudinal elastic waves.
Claim 8
Dependent Claim
29 words
A method as claimed in claim 1 and in which said bias field is applied substantially parallel to the direction of propagation of the elastic waves in said medium.
Claim 9
Dependent Claim
31 words
A method as claimed in claim 1 and in which said bias field is applied at an angle inclined to the direction of propagation of the elastic waves in the medium.
Claim 10
Dependent Claim
59 words
A method as claimed in claim 1 and in which the steps of claim 1 are then repeated in a cascaded second magnetic-elastic medium with different magnetic fields to form a bandpass characteristic between the spin-wave-converted absorption frequencies of the media, and varying said fields to vary at least one of the width and center frequency of such bandpass.
Claim 11
Dependent Claim
21 words
A method as claimed in claim 1 and in which successive portions of said medium are provided with different saturation magnetization.
Claim 12
Dependent Claim
143 words
A tunable electromagnetic wave filter having, in combination, a magneto-elastic medium provided at opposing surfaces with electromagnetic energy-to-elastic wave energy transducers, means for applying a band of electromagnetic wave frequencies to one transducer to convert the same to corresponding elastic waves that may then propagate through the medium to the other transducer at which the elastic waves are re-converted back into electromagnetic waves, means for applying to the medium a magnetic field curved profile and bias magnetic field that intersects the same at points corresponding to specified frequencies of said band, the field at such regions effecting conversion of the elastic waves of the specified frequencies only to spin waves with attendant absorption of the energy thereof, and means for varying the bias magnetic field to vary the position of said regions and thus to vary the specified frequencies to be filtered out.
Claim 13
Dependent Claim
143 words
A tunable electromagnetic wave filter having, in combination, a magneto-elastic medium provided at opposing surfaces with electromagnetic energy-to-elastic wave energy transducers, means for applying a band of electromagnetic wave frequencies to one transducer to convert the same to corresponding elastic waves that may then propagate through the medium to the other transducer at which the elastic waves are re-converted back into electromagnetic waves, means for applying to the medium a magnetic field curved profile and bias magnetic field that intersects the same at points corresponding to specified frequencies of said band, the field at such regions effecting conversion of the elastic waves of the specified frequencies only to spin waves with attendant absorption of the energy thereof, and means for varying the bias magnetic field to vary the position of said regions and thus to vary the specified frequencies to be filtered out.
Claim 14
Dependent Claim
15 words
A filter as claimed in claim 11 and in which said medium comprises YIG material.
Claim 15
Dependent Claim
29 words
A filter as claimed in claim 11 and in which said field applying means is adjusted to produce a profile curve that rises and then falls along the medium.
Claim 16
Dependent Claim
29 words
A filter as claimed in claim 11 and in which said field applying means is adjusted to produce a profile curve that falls and then rises along the medium.
Claim 17
Dependent Claim
32 words
A filter as claimed in claim 11 and in which said field applying means is adjusted to produce a profile curve that rises and falls a plurality of times along the medium.
Claim 18
Dependent Claim
18 words
A filter as claimed in claim 11 and in which said transducers are electromagnetic energy-to-longitudinal elastic wave transducers.
Claim 19
Dependent Claim
21 words
A filter as claimed in claim 11 connected in cascade with a second similar filter but with a different magnetic field.
Claim 20
Dependent Claim
18 words
A filter as claimed in claim 11 having successive portions of said medium of different saturation magnetization values.
Claim 21
Dependent Claim
29 words
A filter as claimed in claim 11 having a central YIG crystal medium externally provided with a plurality of poly-crystal YIG portions of greater and lesser saturation magnetization values.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |